squab vs couch

squab and couch both are nouns.

Word	Noun	Adjective	Verb	Adverb
squab	Yes	Yes	No	No
couch	Yes	No	Yes	No

As nouns, couch is a hypernym of squab; that is, couch is a word with a broader meaning than squab:

Other hypernyms of squab include lounge, sofa.

squab (noun)	couch (noun)
an unfledged pigeon	an upholstered seat for more than one person
a soft padded sofa	a narrow bed on which a patient lies during psychiatric or psychoanalytic treatment
flesh of a pigeon suitable for roasting or braising; flesh of a dove (young squab) may be broiled	a flat coat of paint or varnish used by artists as a primer

squab (adjective)	couch (adjective)
short and fat

squab (verb)	couch (verb)
	formulate in a particular style or language